The dispatcher only re-paired on an ABSENT cookie. After the 2026-06-09
auth-schema rollback wiped all server-side sessions, browsers kept dead
30-day t3_session cookies; the dispatcher proxied them straight through
and t3 rendered its pair page ("all users must pair again").
Now a present cookie on a top-level document navigation is validated via
the instance's /api/auth/session and re-paired on authenticated:false.
Gated to document navs (Sec-Fetch-Dest: document, else Accept: text/html)
so XHR/asset/WebSocket sub-requests are never answered with a 302; fails
open (proxy through) on any validation error. Unit + handler tests added.
[ci skip]
Co-Authored-By: Claude <noreply@anthropic.com>
